SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '508dc4457d1925b2bc1794daabd05e37d6cb72770caf8623f578fc3ee940d1ca' 
  AND token = 'bPC7VdXsXlQ7l8VwzilWTfn74XlD/auGhBOjJwwqwNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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