SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b71ec176a38ac528c7fcc730eca54c23dc747912dbf51f8944e0a70df9624c1a' 
  AND token = 'ti/jLg7/VriOFiOKOSd8vFwseK/heheL/qJn1hqLlWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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