SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5f7fee7eaa9138b68e754d173e0e18430648598c04d0be46aafd3a4d66b2909' 
  AND token = 'hzaE1DudDTu7jC0fck7IG0gii7rKiJ/J2TA5BlBNDYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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