SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9871002aae2945e895bf54a8902ab88ca35710acd5d15a0b8c201f7a88bb0a3' 
  AND token = '5qE54LCW1CHQ3EiPFTWCwyt2oB8UupAQLOfdJnFkJX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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