SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72792a4db8904907ac376125d1d37c3a55136dcf17b51964355d8f47d8460ee5' 
  AND token = 'z8OrEjhxIPky1GElLJU7HzALp28Fijxy+OPBujFRhso=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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