SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd068fc20bc46ee982c0e53b943fdaf441d29edfa398c1211584daf49a93685b3' 
  AND token = '+veZ6hGn2BImtVZr+hV1trw/ZbGx1fUz6YYwxG/XIgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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