SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f47029ad01dddd9e1b23b53d01685c5c81637841e373b3c435a5f300c2df942' 
  AND token = '9zUR+1q+RIRIiXAUXufs05IghPKsTCD6TmuBJgkA+s4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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