SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7aa3ee5698a85298647c176434e5dd77140905cb9e3c8beb05e602f39d093f70' 
  AND token = 'h1k7Jwutn9bsVYO//xDYqGNT+Q2qlz2xJtWS1n2vFKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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