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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '345cfabc3cd90d8c5ca05469b34f2aeab437e25dc2d4f59201ecc361d11f5d2d' 
  AND token = 'NPrjI53nTjO/N+NN7ysEScC+hbz8UaPHZVoBf4/t0Zc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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