SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '313950c037c5c1d898104da6fc0b11909fb4be52c1fd655393eb496c5d62d0c7' 
  AND token = 'wekI2E4/owKLijr5/PYAcd3z1/7IhSAncHCNwgFoh5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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