SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af17a9e6e3b9690b4b196b5a07c8299427fa3ed8567f2853ed8c978999205c2e' 
  AND token = 'e9DEwfAf8cTqZyLsnAiDcowpVGmqg7kLQEOMUs7RbP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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