SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21c08cf04be9329f2290efdf3d26632b853051238c99e19522d5180875037200' 
  AND token = '93qvZQx32yYVYX2X2dFenv/VmQrdngp8NAJz0Ompkxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}