SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84474beb47630bacaae1e3f0683c621ce82dd87ec1a24102010c4d8502fd6e31' 
  AND token = 'R5a5kqlf2iyVOZNIs2kVQdaux1XuSaZmivzxZ/npCZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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