SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd36f33ed6036f3ef1855c4833b472692eef17791530910783d90e25e9ed3a1c' 
  AND token = 'IiMuNWYmdaUszOeAXqy01IfGY+ARGLoRlTvlyBiu7so=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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