SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83527464957c984011f77885ec5f90fe017db77382e822d7d4ec5df4145e089e' 
  AND token = 'ejoJmWhvhNH/TY26mggWfTiYLnvoBvKG9QeH9QF+m8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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