SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90b88bc2e9efcbc627b10d42be61df8911aefe937d02bd90c96b5c420a966b29' 
  AND token = 'U2MqbxJ2FRASKl0+OWYefje3InEKMzJxlSd26tFNVnI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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