SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c3551877c524b845e246f32f71b2f2642552dae1827c8f9384a4649611b6ed3' 
  AND token = 'ZgHW5sPsZqGLffjqpjdgi+kmNkEXtUHUO0k4JVG7E2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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