SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74acefd83b652ef1ded4343279e9be47fe640159ac2cf4e06f7b07cbfd87d673' 
  AND token = 'j+kSBBwHqzjC1u4bBNL3K9vm1An/NtOaSyTpJhpwsAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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