SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3a0e1d1ff865cb4c61892a3b50d53022dc2a934ae64092c0475729fb34e56a8a' 
  AND token = 'mEqmhl2BS6M0ztKGhzEthHp2OGOQ8GfCnzVmVUt07pQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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