SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f9113cab48bb435eff537852f24cd6ac21604ccbf6902c7572e35fe20a88e40' 
  AND token = 'M2jYhthfJeMJVAGp0NnKoZ8dqstDxYRgLDxYztaR/OE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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