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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6ca9b6b911c3538f0b1ffbdcbaedf2a09b22dd36e6a2c0c0ba86064180e11b0a' 
  AND token = 'W6rNCplTrXnSjkS97XwLiiBeCDo5r5sMCyRpVghucuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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