SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17065d5bbc79b3896cfdcd80612e068abd99580297492165c222b3ac6a89021b' 
  AND token = 'RbIxgYQDFZVouWHpqBw2yFe3J8cegAcQYLxubmehjYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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