SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c448a843ae0fbd03a9dcd6d1f9a3a75b098779d09d0f40b27f3ee31b75117c94' 
  AND token = 'qMvP/xlOGq7B6fYhWRvhSs+BWE6hsP1SOTZH35jYjWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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