SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40cc4df686c2520b7146f1fe6e421542967a7697f59fc097defeb35385a81dc3' 
  AND token = 'O15ZDeVJjPg3WFPsGchhaYvU3aFGF4BfxLkEgJVUd3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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