SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feadd30bafc766d95a0173995d51dec6e2a555da89a160f70e1bc80594575b63' 
  AND token = '4hYVlHGGhP6daCymGTgc324zwp+BQTCmb7/EI1UaLL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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