SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a844b364789f4627f52a2fcdfb207289089375db3f6ea8c6aeaed7f32961fc9b' 
  AND token = 'wr5DBWTwwXf7n0NdIh0SBypGFtpFtjuMMCo3EEE2ST4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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