SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5ecad711db4b6966ba91361bb5a00a42bad2d3546b5e647196aad77aa0e925a' 
  AND token = 'S0jaaU4UHXdbpeKlTfz5DzcFPAHTF2bO4D0WQJiC2sg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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