SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42ce5722d06441fd0dcc7a70e3e5343a7cb20c9012d8a92533674525b9f75ec9' 
  AND token = '+2CXJiqYqkoC6Y1nNmlvUgpk97jt6ddTzpoaqAydykk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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