SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3550be76b164758059b0b465516f4795d961be6f42575b46ff6a381964bec3a' 
  AND token = '6saN/EgBMuhbdBRQlcL+fWkXARomUh6662TPOPl/7vA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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