SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192a7ed22af27db42ff6fe3868d9f90fefdbdce3827cb2f17f3c3a8f0db83ca0' 
  AND token = 'I8K3dANq3kInid5X4z8lTCy2CCcrbIUzly3b7ApTSAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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