SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e4bf4a338245f367290d856c78c7e1b0c56a1475898270aecf365869bd55042' 
  AND token = 'rKUKldoPBTo+t1ycqcECxNwTD/2JgWhwuNFoyy2fUeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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