SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f5b3deecfa4f1a61f18cd36908095e82b5a21c5474d4e30218e873c6afeb9e2d' 
  AND token = 'u7gNgYvOTvmQ6UVp3KvcRQEhA5q/+K0RfyqevuKur1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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