SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '188b44fc7aff37768ad1cae50457436d1079c2ff23c41ffd4bb9d62a5661ece5' 
  AND token = 'kqyg5zHJwSRO1rf26MmFcdlmo/vS3p66YzDNah0uDmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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