SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0f2ecaf166abac98b34223d1cd30a5c41dcc69496e0b76d929f31334ae44594' 
  AND token = 'nOZ9Cpam3bAL+Qptg5HNiPISbE6qdOOVvSdlIWessH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}