SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2d97d94bd9210837f8dc2ff2043e8c3a0196cd6222d2998d1024bd76a5e34e9' 
  AND token = 'Fb6Ui2O/7qzMWkgFIABBGWMm9LUEZnbIaE12zlaXpDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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