SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baaf7d69b696174bb9054d2c859e5666810873290561fd1f1a1e365787becef2' 
  AND token = '/ydPLDJ+KDUuFH7mCCqp0wgE9VdZC4tQ4suMP95bpw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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