SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8759c4bdf3293ddd7b11fdd585be39323e900f291f705bbd916a076d1e61926' 
  AND token = 'SBnGA4Kfjg7x7+ZizYKYrsMu1mwANrOvIkQ2hYy4pmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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