SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c8e125a31dbad5466dc9a287532275f5a2572f4eb08002ceea68b78efb0dfb8' 
  AND token = 'k+CYMP4RCk/zn7wZlnymLgFq/vkzFQlPad4bwYtyn6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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