SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f329cd75cf05886d2aade159d56d6cc61e180b57ecc4afa6e078deee9714fd2' 
  AND token = 'dpBj4EwP+oxlLdUCEMDEUvQ5wPqP5LUuw74vRhiMk0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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