SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b4ea6e3c5a3b11489d0d376ac0afc4c978869d39361c73c62d02c27999576d5' 
  AND token = 'LBCvbZHoMEJVmQ8GktOHHh+tH5HVXXa4EyfLDCZjGCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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