SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a6e50709297589f884c5d549d1917fce8274e71841a8cdfee9852bc3d1fafcc' 
  AND token = 'Aw8SHpxRrSvfp6WN/59my5/cr1K5n8Da7YVSjhCYdso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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