SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2de6be21516e37424147bcfbaf3e2efffd35cc3759dfde77fc5f6be6da0cb8e' 
  AND token = 'xEaJ/6BS/NKKwYX8zEyhk6bmme8eDILFXqDNilsld0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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