SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f68d44e40e24319306b2265ef4a463c3fa69c175174e2412261db4ece896b550' 
  AND token = 'tuLubmcK9QovQZW2SCYS3mCNZetca/jhIQjdzKGVQG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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