SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcf6df304d025fa48de3795a0577dc28641f32b02d97b5307e68079110b17714' 
  AND token = 'iprRcuiJ1OXhqqlsVubE5kyz2dS+JgEgnrcUpzyXo8A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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