SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b269e9557ac5ef8f915f8a4ea41dc7662432fe1ee103f020d1daffa308937fbd' 
  AND token = 'BYaiB0acHdyxe5J1KufswCRBioVWHxQda7UKYNiRMoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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