SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8634fe16ba4175b5ea26dd25b158a876cd8f263ff96521c635902c051bd6d14a' 
  AND token = 'cXqmRAL7XcLEqIdyWpmYE1DtBjS80P+uNI7vXrURJQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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