SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '426a5bb03434fe7250c4756644d5f86f855874380ca1aea99444f86efc55514a' 
  AND token = 'EEOnEsmOofsYG+R0cd2V2Ya9pyOozwRHKfGn+SnSVYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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